<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <script src="js/vue.js"></script>
</head>
<body>
    <div class="box">
        <input type="text" v-model="username">
        <hr>
        <!-- 下拉菜单 -->
        <select name="" id="" v-model="cyte">
            <option value="">选择城市</option>
            <option value="1">北京</option>
            <option value="2">上海</option>
            <option value="3">广州</option>
        </select>
    </div>
    <script>
        const vm = new Vue({
            el: '.box',
            data:{
                username: 'zhangsan',
                cyte: ''
            }
        })
    </script>
</body>
</html>